Thoughts on PERSIST construction in Chattanooga, zone 4a
I'm designing my home using the PERSIST technique and would like input on insulation ratios that are suitable for my climate zone. I'm in Chattanooga, climate zone 4a, with 3587 heating degree days and 1544 cooling degree days.
Practically speaking, we have 3 months of trying to stay warm, and 8 months of desperately trying to stay cool.
My plan is a 1200 square foot, 2 story, flat-roofed house with a simple footprint, oriented for passive heating, windows placed accordingly.
I'm wrapping the OSB sheathing in Ice & Water shield (including the roof), layering to 3" of EPS for outsulation (r-15), then furring and metal siding. The 2x4 walls will be covered inside with 1x6 t&g boards (no drywall, no cavity insulation, which seems crazy).
The foundation is a raised, floating slab on concrete stem walls, all insulated with 2" borate-treated EPS, and with serious detailing at the mudsill.
The problem I'm having is an effective "case study" in my region with which to compare this to, and of the many questions I'm having, the issue of whether to insulate the cavities at all (given the R-values and lack of thermal bridging of the wall assembly I've described above), and whether my interior finish needs to be replaced with airtight drywall.
Posted Tue, 02/25/2014 - 13:47
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